A few more details, omitted for brevity in my first post:
While the noise is present everywhere, it is not truly broadband. Listening
at HF with the IC-746, it is a series of broadband signals spaced every 20
KHz, with the noise falling off toward the edge to a fairly quiet KHz or two
between these signals. On the IC-746 spectrum scope, it looks like a full
wave
rectified sine wave. Imbedded near the center of each band is a weak CW
carrier, very slightly unstable in frequency.
On VHF with the AM detector in my FT-7800 it appears as a broadband signal.
I made those observations a while back. Now that I can create the problem
while parked (by moving the steering wheel), I can safely look further, though
don't expect I could learn much more.
QSL on the use of braid for grounding. I am using #12 TW wire, with lots of
Liquid Electrical Tape covering the connections. I've made a mental note to
check them when snow and salt season is over.
73 - Jim K8MR
In a message dated 1/17/2008 6:22:00 P.M. Eastern Standard Time,
dgsvetan@rockwellcollins.com writes:
Jim,
If you contact someone at Honda with technical knowledge, try to find out
what motor type the EPS uses and how it is controlled. In short: is the
motor a permanent magnet DC type with brushes, or is it operated as a
servo motor? Does the controller use PWM or variable frequency to set
motor speed and/or torque? Depending upon the answers to those questions,
it may be possible for you to determine a cure if they can't.
One other comment: If you used braid for the exhaust pipe grounding, keep
an eye on it periodically. I found that tinned copper braid lasted about
18 months before corroding away when placed under a vehicle and in contact
with that hot pipe. It was very effective until that happened.
73, Dale
WA9ENA
To rfi@contesting.com, xxw0qe@comcast.net, mathenyr@marietta.edu,
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cc
Subject
[RFI] Honda RFI
Last August I bought a new 2007 Honda Fit. While the ignition noise
seemed
reasonable, especially after adding a few easily done exhaust pipe
grounds,
there remained a mysterious broadband noise noticeable on all bands at
least
through 2 meters. It is worst on 15 meters where it was S9 on a HamStick.
It
had an odd pattern of being on most, but not all, of the time, and not
when
moving.
Today I had the Eureka moment, and have determined it is the Electric
Power
Steering (EPS). In particular, it begins immediately upon any movement of
the
steering wheel, and continues for about 2 seconds after the last movement.
Hence, no noise when parked. Driving down a straight road with hands off
the
wheel, it remains quiet until I move the wheel.
Do any Honda owners with models equipped with EPS also experience this
noise? I am curious if it is a problem extending beyond the Fit. A brief
test in
a new Accord at the local dealer was inconclusive, in part because there
was
a lot of other RFI in the lot where we tested it. I plan to contact
Honda's
1-800 customer service number in a few days (the local service people, and
a
regional customer relations person were very unhelpful once we determined
that
another Fit had the same problem). The problem in my Fit is also
noticeable
in the FM broadcast reception on weaker stations, so it may be of
interest (I
hope) to Honda on that basis.
Note that it requires an AM detector (or product detector) to observe
this
noise. A VHF FM radio is not likely to hear it.
When the weather warms up I plan to remove the EPS fuse (a 50 amp, screw
down type) for a some low speed experiments in an open parking lot. Would
disabling the EPS likely be a safety issue, at least for open highway
driving?
73 - Jim K8MR
**************Start the year off right. Easy ways to stay in shape.
http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
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